Petersson derived from Proto-Indo-European*bud-, *bewd-(“to swell”), together with պտուկ(ptuk). This is accepted by Pokorny and J̌ahukyan. Ačaṙean remarks that this etymology is formally acceptable and for the suffix -ուղ(-uł) compares -իլ(-il), -աղ(-ał), but he does not accept the etymology because of the absence of reflexes with the meaning “fruit”.